> >A raindrop falls from at least 500 meters of height and has > >a minimum size. I'd use a simple microphone attached to a > >drum-like structure (with saran wrap skin I think). This may > >react to other things besides rain. > > Well yeah, if it is actually raining, in a "cats and dogs" sense. But often > when I'm driving my car, the road is wet, and there is misty water landing > on the wind screen, so there is some precipitation of moisture out of the > atmosphere. It certainly does not land on the windscreen with enough energy > to make any noise. FWIW - a raindrop has a terminal velocity of a few tens of kilometres per second. Actual velocity depends on drop size but in free fall is never vast. I imagine that wind blown drops assume a speed approaching that of the wind gust they are carried by. RM -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.